webdevtim,
We have some plans to integrate better into the standard menu system for an upcoming release. However, what you're looking to do is much more difficult to work on everyone's website, and something we likely won't be doing soon. Let me explain
We already have plans to allow you to create direct login links to each of the social networks we support via a menu item. That way, you can create you're own "Login" drop down menu with specific menu item links Facebook, Google+ and LinkedIn, for instance.
However, we're not planning to let you insert the whole SCLogin module inside a menu item because of all the issues that you just brought up: it'd be very hard to do this in a compatible way with all the available template and menu systems out there. In the case of the above, and especially on responsive sites, the best recommendation we'd have when the above is implemented is a custom menu item with links for the social networks and a final link for "standard login". That can bring the user to your fully features, responsive login page and they can enter the site that way.
I hope that helps explain, but if you feel I'm missing something, just let me know.
Thanks,
Alex